Toothed gearing



Feb. 11, 1930. H, D, WILUMS 1,746,571

TOOTHED GEARING "original Filed July 25, 1914 Si vwewtoz v./Zfnrvy.Williams Patented Feb. 11, 1930 y UNITED STATES PATENT OFFICE HARVEY D.WILLIAMS, OF WALLINGFORD, CONNECTICUT, ASSIGNOR, BY MESNE ASSIGNMENTS,TO SECURITY TRUST COMPANY, OF DETROIT, MICHIGAN, A COR- PORATION 0FMICHIGAN TOOTI'IED GEARING- Original application led July 25, 1914,Serial No. 853,017, and in Great Britain May 6, 1914. Divided and thisapplication filed September 20, 1919.

My present invention, for which I have filed applications in GreatBritain May 6, 1914, and in France October 6, 1914, relates to gearwheels, and has particular' reference to that type of gearing in whichtwo succes sive working tooth-surfaces (whether on the same tooth or atthe same tooth-space) constitute a pair related in a particular mannerto a master-form axis7 located between the two tooth-surfaces of saidpair. My invention is designed for use in cases in which one of themeshing gears (hereinafter referred t0 as the wheel) has its workingtoothesurfaces formed according to a single-reproduci tionconfiguration, while the other gear (hereinafter referred to as thepinion) has its working tooth-surfaces formed according to acompoundreproduction configuration and conjugate to those of the saidwheel. The present application is a division of my application forLetters Patent filed in the United States Patent Oliice on July 25,1914, Serial No. 853,017, and renewed on December 5, 1917, Serial No.205,664, on which Letters Patent No. 1,324,287 were issued on December9th, 1919.

Most of the figures of the drawingsA of my said Letters Patent disclosea form of my invention in which the master-form axis lying `between thetwo tooth-surfaces of the same pair, on the wheel, is a straight line,so that both surfaces of such pair may be produced in a very simplemanner, by the rectilinear reciprocation of a tool the profile of whichcorresponds to that of a tooth or of a tooth-space. According to thespecies of my invention forming the subject-matter of thepresent'application, the two surfaces of the same pair,von the wheelhaving tooth-` surfaces of single-reproduction configuration, are suchas may be produced by the motion of a suitable tool along a curvilinearpath, and more particularly, along a circular arc, that is to say, themaster-form axis is nolonger straight, but curved, preferably accordingto the arc of a circle. The present species of my invention was alsodescribed andA illustrated in my earlier application above referred to,`at the time of its ling.

-z-.Reference is to behad to the accompanyy adjacent tooth-spaces.

Serial No. 325,216.

ing` drawings, in which Fig. 1 is a partial end view of a spur wheel anda mating pinion embodying this invention; Fig. 2 is a face view showinga portion of the peripheral surface or tooth-Zone of the wheel shown inFig. 1; Fig. 3 is a partial face view of the tooth-Zone of a bevel wheelformed according to this invention; Fig. 4 is a similar parta?L view ofa skew bevel wheel embodying this invention; Fig. 5 is a cross sectionon line 5-5 of Figs. 2, 3, and 4; Fig. 6 is a cross section of anotherform of the wheel, taken on the same plane as Fig. 5; Fig. 7 is aperspective view of a portion of a bevel pinion constructed according tothis invention; and Fig. 8 is a diagram illustrating certain re'-lations set forth hereinafter; and Fig. 9 is an end view of the toolsemployed for cutting the working tooth-surfaces on the wheel and on thepinion.

In Figs.'1 and 2, I have shown a spur wheel B having a tooth-zone Nacross which ex tend the skew working tooth-surfaces arranged in pairs,the two surfaces of the same pair, as f3, f5, being formed oflongitudinal circular-arc elements all parallel to a circular-arcmaster-form axis w13 which lies between said tooth-surfaces andintersects obliquely the two planes at the ends of said tooth-zone. Inthe particular case here shown, the surfaces f3, are at the sainetooth-space F, and h indicates a portion of the tooth lying in thetooth-zone between two The axis of the wheel is indicated at ma, and theparallel axis of the mating spur pinion P at d, while m designates theinstant axis which is parallel to the axes m3 and (l and whichintersects the mas ter-form axis w18 at a point half-way between the endsurfaces of the tooth-zone, which point lies on` the median pitch-circle7 of the wheel B and on the median pitch-circle 8 of the pinion P', thelatter having teeth g the working surfaces of which are conjugate tothose of the wheel, as will be set forth more fully hereinafter. At e,Fig. 2, I have indicated the angle of Obliquity which the mas-- ter-formaxis (that is, a tooth-zone secant thereto) forms with the instant axism.' Inasmuch as the surfaces f3, ffconsist of'curvif` linear'longitudinal elements all parallel to the same master-form axis m13, thelatter being a circular arc, it will be obvious that both surfaces ofthe same pair may be produced at the same time by moving (rotating) in acorresponding circular path, a tool, such as .I (Fig. 9) having the samecross sectional shape as the tooth-space, the shape of the latter beingshown best in Fig. 5. The wheel or Wheel-blank would remain stationaryduring this production of a pair of tooth-surfaces, so that they may besaid to be formed according to a single-reproduction configuration. Itwill be obvious that when the wheel and pinion are rotating in a certaindirection, say the one indicated by the arrow i in Fig. l, only onesurface of each pair of surfaces of the wheel and of the pinion will bein driving (fo-operation, the other surfaces of such pairs acting simplyto prevent backlash. Inasmuch as generally it is desirable to have thegears transmit power equally well in either direction, I prefer to havethe two tooth-surfaces of the same pair disposed symmetrically to thecentral line m2 which intersects the master-form axis see Figs. 5 and8).

In Fig. 3 I have illustrated a bevel wheel with tooth-surfaces arrangedin pairs, the two tooth-surfaces of the same pair having the samerelation to each other and to their master-forni axis as in Figs. l and0. The secants subten ding the tooth-zone arcs of the master-form axes mof the several pairs of tooth-surfaces f3, f5, will, if extended, passthrough the apex 0 of the wheel-cone, of which the tooth-Zone N formspart; the secants subtending the longitudinal arcs at the bottom edgesof the working tooth-surfaces are substantially tangential to a circle253, and the secants subtending the longitudinal arcs at the upper edgesof said tooth-surfaces are substantially tangential to a circle 1', eachof said circles having its center on the axis of the wheel-cone. Thespacing of adjacent master-form axes m is uniform, as indicated by theangle or arc Z, but-owing to the forniation on the tooth-surfaces ofthesaine pair, of parallel longitudinal line-elements, each action-face ordriving face of the wheel, say f", has a rearward skew, the extent ofwhich. is indicated by the angle or are cl3. The wheel teeth hintervening between the adjacent tooth-spaces F are tapered inwardly.The tooth-spaces themselves are of 'uniform width or crosssection fromend to end, if such cross section be taken in planes perpendicular tothe respective master-form axis m. It will be seen that a pair ofsurfaces, such as 2l and 22, formed of parallel longitudinal elements,is, followed by another pair of surfaces, as 23 and 24;, also composedof parallel longitudinalelements, but the rlongitudinal lineelements ofthe surfaces 2l, 22 are not parallel to the similar elements of thesurfaces 23 Q4, but in a` convergent. relation thereto, as ndicated bythe angle Z2. Thus, of any three sucd cessive tooth-surfaces, two havethe same master-forni axis and are composed of longitudinal circular-arcelements parallel to said axis, while the third surface has longitudinalline elements parallel to another master-form axis. This relation asregards the working tooth-surfaces of the wheelis true of all forms ofmy invention shown herein.

In Fig. t I have illustrated what may be termed a skew bevel wheelhaving working tooth-surfaces arranged in pairs on the toothzone l ofthe wheel body B, in substantially the same manner as described withreference to Fig. The difference lies in the direction of the tooth-zonesecants subtending the master-form axes, indicated at m12, whichsecants, instead of passing through the axis of the cone (as does theinstant axis have a strong Obliquity or skew, as indicated by the anglee6. The axes m12 are circular arcs as before.

The rearward skew indicated at cl3 in Fig. 3, and the similar butgreater skew obtained with the arrangement shown in Fig. 4, result in avery gradual meshing of such wheels with their respective pinions, thussecuring a very smooth operation.

As stated above, any one of the three kinds of wheels shown, may haveits tooth-surfaces formed in pairs, by moving (rotating) in a pathcorresponding to the position of the corresponding master-form aXes m13,or x12 respectively, a tool, such as J in Fig. 9, having a profilecorresponding to that of the tooth-space F (Fig. 5), the wheel body orblank being held stationary during the motion of the tool. Of course, arelative circumferential movement of the blank and tool (the so-calledindeXing) is eifected after one pair of tooth-surfaces has beencompleted, to bring the tool into working relation to another pair oftooth-surfaces.

YThe pinion P (Figs. l and 7) is formed with teeth g the workingtooth-surfaces of which, j2, terminate at the tooth-zone in edges Thesetooth-surfaces may be formed in pairs by means of a tool, such as T,which is a counterpart of the tool J employed for forming a pair oftooth-surfaces on the wheel. lVhile in the case of the wheel, theproiileof the tool I is shown as corresponding to that of a tooth-space F, sothat said tool may produce at the same time two tooth-surfaces locatedat the saine tooth-space, the correspond ing pinion-cutting tool T hasaprofile correspending to that of thecross 'section of" a pinion-toothg, so that said tool may produce at the same time two tooth-surfaces onthe same tooth. The operation mi ghtV be reversed, that is, the tool kTmight be Iemployed to cut a pair of tooth-surfaces f3, 'f5 on the sametooth ofthe wheel B, as'inidicated yin Fig. 6, in which i 'casether'counterpart tools J would be employed iforf" producing i onl thepinionP, pairsoftooth-su`rfaces, eachpair being at theasametooth-space.` `lNhether` the tool J or the tool T isemployedinconjunction with the wheel B, theinotion of such tool` `would be in acurvilinear path, and preferably in the arc of a circle, as referred toabove..` In cuttinguthe pinion tooth-surfaces, the pinion blank and thetool would be given a relative `movement such as'the toothfsurfaces ofthe wheelhave relatively `to those ofthe` pinion whenthese two gears areoperating in mesh with one another, the pinion-.cutting toolcorresponding to the toothsurfaces of the Wheel, or rather to a pair ofconsecutive.tootlnsurfaces of the wheel.` In

addition to this relative rolling movement of` the tool and pinionblank, the tool would be given a longitudinal cutting movement in acurved path, and specifically in a circular arc, so that at one cuttingmovement'or cutrtingstrolre of the tool, two points ofsaidtool will cutlongitudinalparallel lines such as i e', e" `on the two tooth-surfacesof the same pair, said lines being arcs ofcircles" corresponding to thepath of the tool. Of-course,

owing to the relative rolling motion just re` ferredto, the pairofparallel lines cut at the next stroke of the tool will not be, parallel(on the surfaces y?) to the pair e', e" first mentioned; still,thetwosurfaces jg of the same pair will be composed of` longitudinal lineelements in the natureoflcircular arcs, each line element of onesurfacehavinga corresponding` lineelement, parallel to it, on the `othersurface of the pair. From the inode of production described itfollowsthat while the two tooth-surfaces of the same pair on the wheel` willhave `an untwisted form or construction, owing to theirsinglewreproduction configuration, the mating pair of conju-V gatepinion tooth-surfaces, owing to their peculiar compoundreproduction.Lconfiguration,..v.vill have a` twist throughout their lenothm 1p p. t i

Iii the diagram Fig. V8, w3 vindi-catesthe axis ofytlie wheel-blank Bumaandmir are circles` of equal radii, having their centers on saidV axisat c and o respectively, and each lying in a plane of rotation, that isto say, these two circles lie in parallel planes perpendicular to theaxis w3; the.circle/m,3 may be saidto be described by the endof the,radius m2 rotating about saidaxis, and this circle indicates thegeometric pitch-surface corresponding tothe pitch-circle 7 indicated inFigs. l and 2. The outer end of the radius m2 is designated as tra?,andlies in the instant axis. At c', g/ I have indicated a radiusparallel to m2, the` `point y `lying on the circle m4. With the pointyas acenter, "andvjwc as a radius, I have drawn a circle m5, having aradius 3b perpendicular to y, c. This circle may be described as theorbital path of the point a (at the outer end of the. radius 3b) aroundthe point y.

L The vertex ma and the points y, a lie in a plane `right-angledtrianglethe plane of which is tangential to the geometric pitch surface, saidsur `acebeingthe geometric surfaceiof revolution generated by the line m(connecting @am with y) revolving about the wheel-axis ma. This trianglema", y, a has its hypotenuse m13 (wai-5) curved according tothe arc of acircle and forming the master-form axisof the pairoftooth-surfaces cuton the wheel by a motioniof the tool in apatli corresponding to said`master-form axis ,in this case, the tooth-Zoneof the wheel (as l inFig.` 2) being 1 located contiguous to the meridian `circle m3 of Fig.8, the geanwheel will be of theparticular kind which I designate as askew-spurl. i In Fig. 8 the position m12 of the master-form axis (Figs.et) is indicated by al dotted` curved line, representing 'aniotherposition ofthe hypotenuse line, and when this location of the,master-forni axis is employed, a\slewbevel wheel having teeth of thecharacter shown in Fig. 4 will result. Thus the inaster-form axiscoincides ineach case with a `plane-triangle hypotenuse line,

, which (in some part of its length) touches the tliecurvilinear formsof the tooth-surfaces having longitudinally-parallel elements, and tothe rectilinear forms disclosed more fully in my pending applicationabove referred to, my present" application is specific' to those formsinwhich themaster-form axis is curvi! linear. `z

It will beunderstood that as thetool J or T performs its cutting action,it is also given the usual feeding movement toward the blank so that itmay cut into the blank more deeply atfsuccessiveworling movements orcutting strokes.

. Iclaim as my invention;

. `l. A gear wheelhaving teeth with working surfaces ofsingle-reproduction configuration, saidsurfaces being arranged in pairsof adjacent surfaces, the two surfaces of the same pair havingcurved-line elements parallel to a` curved master-form axis located be-`tween the surfacesof such pair. i

1` 2. A gear `wheel having teeth with working-surfaces ofsingleereproduction` congurations, said surfaces being arranged in pairsof adjacentsurfaces, the two surfaces of the same pair havingline-elements of circular curvatureparallel to a master-form axis ofcircular curvature located between the surfaces of such pair.

3. A pinion having teeth with Workingsurfaces of compound-reproductionconfiguration conjugate to tooth-,surfaces of single-reproductionconfiguration containing Vparallel curved-line elements extendinglengthwise of the last-named tooth-surfaces.

4. A pinion havin teeth with workingsurfaces of compoun -reproductionconfiguration conjugate to tooth surfaces of singlereproductionconfiguration containing parallel' longitudinal line elements ofcircular curvature.

5. A pair of toothed gears adapted to mesh, one of said gears havingteeth with workingsurfaces of single-reproduction configurationcontaining parallel longitudinal curvedline elements, and the matinggear having teeth with working-surfaces of compoundreproductionconfiguration conjugate to the said tooth-surfaces ofsingle-reproduction configuration.

6. A pair of toothed gears adapted to mesh, one of said gears havingteeth with workingsurfaces of single-reproduction configurationcontaining parallel longitudinal line elements of circular curvature,and the mating gear havin teeth with working-surfaces of cornpoun-reproduction configuration conjugate to said tooth-surfaces ofsingle-reproduction configuration.

7. The herein described improvement in toothed gearing, it consisting ina pair of gears comprising a master-wheel provided with teeth eachhaving a working-surface with uniform profiles throughout the lengththereof and each surface having surface elements parallel with ageometric master-form axis which coincides with the curvilinearhypotenuse of a curved sided plane-triangle another side of which, at aplurality of points in the length thereof, coincides with a lineV lyingin a geometric plane passing through the wheel axis, the vertex of saidtriangle being in the instant axis of said gears, and said wheel toothworking surfaces conforming to the single-reproduction configuration,

in combination with a mating pinion having wheel-engaging teeth eachprovided. with a working surface conjugate to said wheeltooth Workingsurfaces and conforming to the compound-reproduction configuration.

8. A bevel gear wheel having curved teeth with working surfaces ofsingle reproduction configuration, said surfaces being arranged in pairsof adjacent surfaces, the two surfaces of the same pair havingl curvedline longitudinal elements parallel to a curved master-form axis locatedbetween such surfaces.

9. A bevel pinion having curved teeth withV working-surfaces ofcompound-reproduction configuration conjugate to tooth-surfaces ofsingle-reproduction configuration containing parallel curved-linelongitudinal elements.

10. A bevel pinion having curved teeth with working-surfaces ofcompound-reproduction configuration conjugate to toothsurfaces ofsingle-reproduction configuration containing parallel longitudinalelements of circular curvature.

ll. A pair of bevel gears adapted to mesh, one of said gears havingcurved teeth with working-surfaces of single-reproduction configurationcontaining parallel longitudinal curved-line elements, and the matinggear having curved teeth with working-surfaces of compound-reproductionconfiguration conjugate to the tooth-surfaces of single-reproductionconfiguration.

12. A bevel pinion having teeth with working surfaces ofcompound-reproduction configuration, said surfaces being arranged inpairs of adjacent surfaces, the two surfaces of the same pair beingconjugate to tooth surfaces containing parallel curved-line longitudinalelements.

13. A gear having teeth fashioned with faces conforming to arcuatesurfaces of different radius respectively, said surfaces generated froma common center.

14. A geared couple consisting of a gear having curved transversegrooves in its tooth-bearing part spaced equally about the axis of thegear, the opposite faces of each individual groove being curved aboutthe same center, and the centers of curvature of the several groovesbeing all diHerent and a complemental gear having a series of teethsimilarly spaced, the opposite faces of each tooth havinnf the samecurvature as the complemental faces of the grooves in the first gear. f

15. A gear constituting one member of a geared couple having curvedteeth and intermediate tooth spaces, the opposite faces of any one toothbeing curved about the same generating center with different radii ofcurvature, and the faces yof ldifferent teeth being curved aboutdifferent generating centers.

16. A gear having teeth with working surfaces of compound reproductionconfiguration, said surfaces being arranged in pairs corresponding toarcuate surfaces of different radius respectively, said surfacesgenerated from a kcommon center.

17. A gear having teeth fashioned with Working surfaces of compoundreproduction configuration, said surfaces conforming to arcuate surfacesof different radius respectively.

I HARVEY D. WILLIAMS.

